NMR Imaging apparatus of changeable inspecting zone size
First Claim
1. An imaging apparatus using nuclear magnetic resonance, comprising:
- field generation means for generating a static magnetic field, a linear gradient magnetic field and a radio frequency magnetic field, respectively, and for exciting nuclear spins in an object to be inspected so as to produce a nuclear magnetic resonant signal when said object is located in a magnetic field having a predetermined spatial gradient;
signal detection means for detecting the nuclear magnetic resonant signal which is indicative of a projection of a nuclear spin distribution in said object to be inspected;
a computer responsive to said signal detection means for calculating an imaging signal;
output means for displaying the imaging signal from said computer; and
control signal generation means for generating a control signal for controlling the intensity of said linear gradient magnetic field, said control signal having a value indicative of the size of said object to be inspected;
said linear gradient magnetic field generation means being responsive to said control signal generation means for providing said predetermined spatial gradient corresponding to said control signal.
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Accused Products
Abstract
In an imaging apparatus using nuclear magnetic resonance which includes apparatus for generating a static magnetic field, a linear gradient magnetic field and a radio frequency magnetic field, respectively, signal detection device for detecting the nuclear magnetic resonant signal from an object to be inspected, a computer for calculating from the detection signal an image and output device for displaying the result of calculation by the computer, the improvement wherein the size of the object to be inspected is detected by use of ultrasonic wave or light beams and a signal indicative of the detected size of the object is applied to the linear gradient magnetic field generation apparatus so as to control the intensity of the linear gradient magnetic field.
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Citations
17 Claims
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1. An imaging apparatus using nuclear magnetic resonance, comprising:
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field generation means for generating a static magnetic field, a linear gradient magnetic field and a radio frequency magnetic field, respectively, and for exciting nuclear spins in an object to be inspected so as to produce a nuclear magnetic resonant signal when said object is located in a magnetic field having a predetermined spatial gradient; signal detection means for detecting the nuclear magnetic resonant signal which is indicative of a projection of a nuclear spin distribution in said object to be inspected; a computer responsive to said signal detection means for calculating an imaging signal; output means for displaying the imaging signal from said computer; and control signal generation means for generating a control signal for controlling the intensity of said linear gradient magnetic field, said control signal having a value indicative of the size of said object to be inspected; said linear gradient magnetic field generation means being responsive to said control signal generation means for providing said predetermined spatial gradient corresponding to said control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An imaging apparatus using nuclear magnetic resonance comprising:
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static field generation means for generating a static magnetic field; exciting means for exciting nuclear spins of an object to be inspected, the object being located within said static magnetic field by applying a radio frequency magnetic field to the object; signal detection means for periodically detecting a nuclear magnetic resonant signal produced by the excitation of the nuclear spins; gradient field generation means for generating a linear gradient magnetic field for application to the object, the gradient magnetic field intensity of the gradient magnetic field being set to a predetermined value at least within a period of detection of the nuclear magnetic resonant signal by the signal detection means so that the nuclear magnetic resonant frequency of the object has a spatial gradient, the nuclear magnetic resonant signal being indicative of a projection of nuclear spin distribution in the object; computer means responsive to the signal detection means for transforming a detected signal therefrom into an imaging signal; output means for displaying an image in response to the imaging signal from the computer means; and control means for generating a control signal for determining the predetermined value of the gradient magnetic field intensity, the predetermined value being determined so as to be inversely proportional with one of the size of the object to be inspected and a size of an inspection zone, the gradient field generation means being responsive to the control signal generated by the control means for generating the linear gradient magnetic field intensity of the predetermined value corresponding to the control signal. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification